Anyone fimilar with 9400i 870cm

[608trucker]

So I have a few concerns I dont know if I'm just looking in the wrong areas or what kinda new to the page. But I'm having a code thrown for sid-251 fmi 2 so its saying there is a power loss to ecm if I'm understanding correctly. Also my voltage gauge stock gauge an aftermarket only read 13.2 to 13.5 an stealership says that's normal but I'm not use to that at all. My other trucks with same motor all read higher then 14. But anyways does anyone know what pin or wires on plug I should look at for this code being thrown I've heard of people running a jump wire but no diagram or pin count if anyone could share some light on this I would be extremely grateful also looking into the future for some off road applications thank you for your time.